Regulating the electronic and optical properties of GaN/InN core/shell nanowires: A first-principles study

2020 ◽  
Vol 34 (25) ◽  
pp. 2050214 ◽  
Author(s):  
Chang Liu ◽  
Enling Li ◽  
Tuo Peng ◽  
Kaifei Bai ◽  
Yanpeng Zheng ◽  
...  

In this paper, electronic and optical properties of GaN/InN core/shell nanowires (CSNWs) have been theoretically investigated through the first principles calculations. The binding energy of In and N atoms on surface of six crystal planes along the [Formula: see text]-axis of GaN nanowires are all negative, which indicate that In and N atoms can be effectively deposited on the surface of GaN nanowires and preparing GaN/InN CSNWs is feasible theoretically. Calculation results of electronic properties indicate that the core/shell ratio and diameter of GaN/InN CSNWs have significant effect on the band structure, bandgap can be effectively adjusted when keeping the number of GaN layers unchanged and changing the number of InN layers. Moreover, with the increase in the number of InN layers, the absorption spectrum of GaN/InN CSNW has significant redshift and few weak absorption peaks appear in the visible light region.

2014 ◽  
Vol 28 (09) ◽  
pp. 1450031 ◽  
Author(s):  
BO QIU ◽  
XIN-GUO YAN ◽  
WEI-QING HUANG ◽  
GUI-FANG HUANG ◽  
CHAO JIAO ◽  
...  

The electronic and optical properties of X-doped (X = Rh, Pd, Ag) cubic SrTiO 3 in perovskite structure are investigated using first-principles calculations. The strength of the Ti–O bonds near the substitutional X impurity is found to be weakened by the shorter X–O bonds. Three types of electronic characteristics due to X-doping are demonstrated. X-doping decreases the band gap of SrTiO 3, extending the optical absorption edge to visible light. Although Pd-doped SrTiO 3 has the greatest absorption in the visible light region, its photocatalytic activity is lower than that of Rh-doped SrTiO 3, because the intermediate bands from the 4d orbitals of the Pd dopant act as recombination centers. The theoretical results coincide with the available experimental results.


2021 ◽  
Vol 21 ◽  
pp. 103827
Author(s):  
Jianrong Wang ◽  
Weibin Zhang ◽  
Qingfeng Wu ◽  
Shufang Gao ◽  
Yuanyuan Jin ◽  
...  

RSC Advances ◽  
2021 ◽  
Vol 11 (42) ◽  
pp. 26432-26443
Author(s):  
Chol-Hyok Ri ◽  
Yun-Sim Kim ◽  
Un-Gi Jong ◽  
Yun-Hyok Kye ◽  
Se-Hun Ryang ◽  
...  

We propose lead-free potassium iodide perovskite solid solutions KBI3 with B-site mixing between Ge/Sn and Mg as potential candidates for photocatalysts based on systematic first-principles calculations.


2014 ◽  
Vol 924 ◽  
pp. 260-268 ◽  
Author(s):  
Hao Chen ◽  
Lan Fang Yao ◽  
Song Lin Yang ◽  
Ya Qin Wang ◽  
Xing Liang ◽  
...  

The crystal structures, band structures, density of states, charge density, overlap population and optical properties of pure anatase TiO2 and Pr-doped anatase TiO2 were studied by using the plane-wave pseudopotential method based on the first-principles. After Pr doping, the valence band and the conduction band moved down and became dense, energy gap became narrow and a impurity band which consists of Pr 4f states appeared. And the dipole moment got improved, which is good for the separate of the electron-hole pairs. These effectively overcome two huge shortcomings of TiO2. Besides, Pr-doped anatase TiO2 produced more carriers which have good transport properties and the absorption spectra of Pr-O bond appear in the region that the wavelength is longer. The calculation results of optical properties show that the absorption edge occured red shift, which means the photocatalytic activity of anatase TiO2 got remarkable improved during visible-light region. This conforms to the previous analysis. So the photocatalytic activity of anatase TiO2 got remarkable improved after Pr doping.


2010 ◽  
Vol 507 (2) ◽  
pp. 356-363 ◽  
Author(s):  
N.A. Noor ◽  
N. Ikram ◽  
S. Ali ◽  
S. Nazir ◽  
S.M. Alay-e-Abbas ◽  
...  

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